Relative Frequency Of Reinforcement Research Articles

MAGNITUDE AND FREQUENCY OF REINFORCEMENT AND FREQUENCIES OF INTERRESPONSE TIMES1

The relative magnitude and relative frequency of reinforcement for two concurrent interresponse times (1.5 to 2.5 sec and 3.5 to 4.5 sec) were simultaneously varied in an experiment in which pigeons obtained grain by pecking on a single key. Visual discriminative stimuli accompanied the two time intervals in which reinforcements were arranged by a one-minute variable-interval schedule. The resulting interresponse times of each of three pigeons fell into two groups; "short" (1.0 to 2.5 sec) and "long" (3.0 to 4.5 sec). Steady-state relative frequencies of these interresponse times were orderly functions of both reinforcement variables. The combined effects of both independent variables were well summarized by a linear function of one variable, relative access to food. Unlike corresponding two-key concurrent variable-interval schedules, the present schedule did not produce an equality between the relative frequency of an operant and either the relative magnitude or the relative frequency of reinforcement of that operant. A tentative account is provided for this difference between one-key and two-key functions.

Behavioral contrast and relative reinforcement frequency in two multiple schedules.

After preliminary variable-interval training, one group of pigeons was trained on a series of multiple variable-interval low-rate reinforcement schedules, while another group was trained on a series of multiple variable-interval fixed-ratio reinforcement schedules. Contrast effects were observed as variable-interval baseline rate changed in a direction away from the change in reinforcement frequency in the other component. The effects of the variable-interval component on performance in the low-rate and fixed-ratio reinforcement components in the multiple schedules were assessed by comparing the birds' performances on each of these schedules alone. Fixed-ratio reinforcement schedules showed a susceptibility to contrast effects, low-rate reinforcement schedules did not. The rate of reinforcement in fixed-ratio schedules at which no interaction occurred in the multiple schedules was higher than that in variable-interval 1-min schedules, suggesting that pigeons may prefer time-based, rather than response-based, reinforcement.

REINFORCEMENT OF LEAST‐FREQUENT SEQUENCES OF CHOICES1

When a pigeon's choices between two keys are probabilistically reinforced, as in discrete trial probability learning procedures and in concurrent variable-interval schedules, the bird tends to maximize, or to choose the alternative with the higher probability of reinforcement. In concurrent variable-interval schedules, steady-state matching, which is an approximate equality between the relative frequency of a response and the relative frequency of reinforcement of that response, has previously been obtained only as a consequence of maximizing. In the present experiment, maximizing was impossible. A choice of one of two keys was reinforced only if it formed, together with the three preceding choices, the sequence of four successive choices that had occurred least often. This sequence was determined by a Bernoulli-trials process with parameter p. Each of three pigeons matched when p was (1/2) or (1/4). Therefore, steady-state matching by individual birds is not always a consequence of maximizing. Choice probability varied between successive reinforcements, and sequential statistics revealed dependencies which were adequately described by a Bernoulli-trials process with p depending on the time since the preceding reinforcement.

Probabilistically reinforced choice behavior in pigeons.

A single principle, "momentary maximizing", may account for much of a pigeon's steady-state behavior in both probability learning and concurrent variable interval experiments. The principle states that a pigeon tends to choose the alternative that momentarily has the higher probability of reinforcement. A successive discrimination procedure, which produced matching in an earlier experiment, produced here a tendency to maximize if training were adequately extended. Maximizing was produced also by other procedures, in which no reinforcing event was presented on some trials: one procedure did and two did not provide a bird with information about the availability of reinforcement on a key after an unreinforced response on the other key. The latter two procedures were analogous to concurrent variable interval schedules in two respects: the reinforcement probability on one key increased while a bird responded on the other key; and they produced matching. But sequential statistics suggested that matching resulted from momentary maximizing. Depending on the procedure, the tendency to maximize produced different relative frequencies of pecking a key for a fixed relative frequency of reinforcement. Computer simulation of maximizing behavior in several concurrent variable interval schedules produced matching and sequential statistics similar to those produced by a real bird.

On some determinants of choice in pigeons.

A pigeon's pecking at each of two or three simultaneously available red keys was reinforced at different frequencies with a conditioned reinforcer, an orange key, on which 25 pecks resulted in a presentation of grain. Pecking was occasionally punished with a period of no reinforcement during which each key was dark. Both with two and with three keys, the relative frequency of pecking on a key was equal to the relative frequency of reinforcement obtained by pecks on that key. Also, the absolute frequency of pecking on each key was a linear function with zero intercept of the absolute frequency of reinforcement associated with that key. The slope of this function varied with the number of available keys; it was steeper with two than with three. The relative frequency of switching from any key (two successive pecks on different keys) approximated a linear function with zero intercept and slope slightly greater than 1.0 of the total relative frequency of reinforcement associated with the keys to which the bird could switch. However, the relative frequency of switching to a particular key often showed systematic irregularities. The invariance in these data is the equality between the relative frequency of pecks on one of two or three keys and the relative frequency of reinforcement associated with that key.

Acquisition and extinction phenomena in human trial-and-error learning under different schedules of reinforcing feedback.

The present program of research on non-verbal selective learning (Noble, 1957a) considers reinforcement ( G ) factors as a major class of experimental variables in human learning and performance. This paper describes an investigation designed to obtain quantitative information about the role of reinforcing feedback schedules in four-choice serial trial-and-error learning by human Ss who performed on the Selective Mathometer. Two widely-accepted generalizations about the effects of partial reinforcement in simple learning situations are ( 1 ) that acquisition rates are faster the higher [he relative frequency of reinforcement and ( 2 ) that resistance to extinction is greater the lower the relative frequency of reinforcement during original learning (Jenkins & Stanley, 1950; Lewis, 1960). Since these two principles are complicated by interactions with task factors, amount of practice, and species differences (Spence, 1960, pp. 91-112), it is necessary to test them under the specific boundary conditions of this research program where human Ss are engaged in complex learning problems for incentives which are not primary. The most comprehensive review of motor-skills learning to date (E. A. Bilodeau & I. McD. Bilodeau, 1961) emphasizes the paucity of our knowledge about frequency schedules in this area.